New Delhi: Reliance Industries and its partner BP plc announced on Thursday an investment of US $6 billion in developing new gas fields in the KG-D6 block after an eight-year hiatus.

RIL chairman Mukesh Ambani said two firms have also agreed on a strategic cooperation on new opportunities for conventional and unconventional fuel trading and marketing including jointly setting up petrol pumps.

RIL is locked in four arbitration cases with the government. It is in arbitration against the government disallowing recovery of certain KG-D6 gas field costs as a punishment for gas output lagging targets.

Another arbitration is over deferring of a natural gas price hike due to the company from April 1, 2014. The latest arbitration is against government demanding US $1.55 billion compensation from RIL and its partners for "unfairly" producing ONGC's gas.